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Endothelin-1 contributes to normocapnic hyperoxic pial artery vasoconstriction
1Departments of Anesthesia and Pharmacology, University of Pennsylvania and The Children's Hospital of Philadelphia, 34th and Civic Center Blvd., Philadelphia, PA 19104, USA.
Brain Research
|October 20, 1999
Summary
High oxygen levels (hyperoxia) cause brain arteries to narrow in newborn pigs. Endothelin-1 (ET-1) plays a key role in this hyperoxic vasoconstriction, impacting cerebral blood flow.
Area of Science:
- Neuroscience
- Cardiovascular Physiology
- Neonatal Research
Background:
- Hyperoxia, or elevated oxygen levels, can affect cerebral blood flow in newborns.
- Endothelin-1 (ET-1) is a potent vasoconstrictor implicated in various vascular conditions.
Purpose of the Study:
- To investigate whether hyperoxia induces pial artery vasoconstriction in newborn pigs.
- To determine the specific role of endothelin-1 (ET-1) in this hyperoxia-induced vascular response.
Main Methods:
- Utilized a closed cranial window model in newborn pigs.
- Induced hyperoxia by ventilating with 100% oxygen and applying oxygenated artificial cerebrospinal fluid (CSF).
- Measured CSF ET-1 levels and pial artery diameter changes, assessing the effect of an ET-1 antagonist (BQ123).
Main Results:
- Hyperoxia significantly increased cerebrospinal fluid (CSF) ET-1 concentrations.
- Hyperoxia induced significant pial artery vasoconstriction.
- Administration of the ET-1 antagonist BQ123 attenuated the hyperoxic vasoconstriction.
Conclusions:
- Endothelin-1 (ET-1) is a significant contributor to pial artery vasoconstriction during hyperoxia in newborn pigs.
- These findings highlight a potential mechanism for altered cerebral blood flow under high oxygen conditions in neonates.